Direction finding system with microrays



Oct. 24, 1933.

A. G. CLAVIER DIRECTION FINDING SYSTEM WITH MIORORAYS Filed Dec. 16, 1931 FIG. 3

INVENTOR ANoR c. CLAVIER ATTORNEY Patented; Oct. 24, 1 933 k PATENT OFFICE ltflCRORAYS I Ajndl' vGQClavital-{Glen Ridgal N. J., assignor to- International" Communications Laboratories, Newarkgflq; J., a corporation of New York I L i A pplication'llecember 16, 1931 H Serial. No. 581,363 I i -clai wa-m This invention relates to direction finding systerns with micro-rays.- a I In my U. I S. LettersiPatent.No. 1 ,928,408 I have disclosed a signaling system which employs micro-rays and a. method of, and" apparatus for,

producing and detecting these rays.

. In U. S. Letters Patent No.1,927,394 granted to Rene H. Darbordgandmyself, there is disclosed a signaling system with micro-rays'in which relay stations are used. between'ithe"transmitting and receiving ends of the system. In the last mentioned patent. it is alsc'dis'closed that such systems may be used for direction finding. This application is a continuation in part of said' last mentioned patent. l

of a fog it iscustomaryfor. the ship to blow its foghorn continually in order to give warning of its presence to any other ships which may be in the vicinity.' In spite of this precaution many collisions occur and a great many others are narrowly averted. When a foghorn is heard in a heavy fog, it is difficult to tell from what direction the sound is coming. Fog, therefore, constitutes probably the principal hazard. of navigation.

An object of this invention is to provide a direction finding system which will be very use ml for short distances and particularly in the case of fog.

Fog also presents one of the major hazards to aerial navigation, and particularly when attempting to land aircraft. If the ground is obscured by fog there is danger, with the present type of aircraft in general commercial use, that an attempted landing will result in disaster. This invention willalso be useful in connection with aerial navigation, and particularly in locating an invisible airport and in making a blind landing.

In the drawing:

Fig. 1 shows schematically one form of my invention;

Fig. 2 shows schematically another form of my invention; and

Fig. 3 shows a circuit which may be used in connection with either of the other figures.

In Fig. 1 means for detecting micro-rays is enclosed within the container 1 and connected by means of transmission line 2 to an antenna consisting of two pairs of antenna sections 3-3 and 4-4 arranged at right angles to one another. Theantennais at the focus of a parabolic reflector 5. A rotatable reflecting screen 6 is mounted with its center opposite the antennae and its axis parallel to the plane of the opening of reflector 55 5. The screen 6 is supported upon a suitable At the present time, when a ship is in the midst FINDING SYSTEM w rn standard 7 and may be rotated by any suitable means, such as worm 8 and pinion 9. The screen 6- is square and its sides should be considerably longer than the longest wavelength for whichthe direction finder is designed, and should never be shorter than twice the longest wavelength, for best reception. It is also advisable to have the screen large with respect to the parabolic reflector 5, so that it will not be completely obscured by the reflector and can-therefore, receive wavescoming from the direction of the reflector. If any transmitting station is in range for: transmitting micro-rays, the screen as it revolves will come to a positionwhere it reflects these rays onto the-antenna system, and they will be detected in the detector. If desired, a scale can beprovided, such as that shownin Fig. 2, for giving an indication of the direction. from which these waves are coming. The transmitting station will be arranged similarly tothe receiving 7:; station, the only difference being that at the transmitter the apparatus will be adjusted for generating oscillations and transmitting them. If desired, a direction finding system may consist of two sets of apparatus, such as that shown so in Fig. 1 or 2, one unit being used only for transmissionand the other unit being used only for reception. Or a device, such as that shown in Fig. 1, may be operated by using it as a transmitter for a certain interval, during which time if desired the reflecting screen 6 may be made to rotate rapidly in order to send a signal which is as nearly continuous as practicable in every direction, and the apparatus may then be adjusted for detection and the screen 6 revolved slowly to pick up any waves which may be incident thereon.

In Fig- 2 an oscillating or detecting system is enclosed in the container 1 connected by means of transmission line 2 to the antenna system 33', 44' which is arranged at the focus of a parabolic reflector 5. In this case the reflector 5 is mounted with the plane of its opening horizontal and the reflecting screen 6 is mounted on a shaft '7 which turns about a vertical axis and may be turned by any suitable means, such as gears 10 and 11. A dial 12 has suitable scale devices thereon which are indicated by a pointer 13. The antenna system in both cases utilizes four quarter wave antennae arranged at right angles.

Micro-rays are peculiarly free from fading, static, or other disturbances and are, consequently, very reliable for use as a fog signal. They require an unobstructed path so that the apparatus will have to be mounted at a point where there is a maximum unobstructed view.

One manner in which the invention may be usefully applied to aerial navigation is by equipping aircraft withmicro-ray devices mounted at the bottom of the fusilage, and equipping airports with suitable transmitters which are located in the center of the held, and sending a conical beam upward. This beammay bearranged so that at a height of '500 ft., say, it spreads out just to the point of covering the landing field. At several thousand feet it will, of course, cover a considerably larger area. An aviator may be guided to the landing field by means of direction finders or radio beacons, such'as those now in use, and when directly over the field will receive a signal from the micro-ray transmitter informing him of this fact. By keeping within the micro-ray beam he may then circle down over the field.

The micro-ray direction finding system -may,

of course, also be used for telephone conversations or for telegraphy. When the aviator is ready to make a. landin he 'may'be informed of the direction from which the wind is blowing.

The transmitting apparatus may be movably mounted so that it can be moved to transmit at an angle in the opposite direction, and if desired the beam may be narrowed by changing the re-- flector 5. The aviator may then again pick up the beam and follow it down to the ground. This will land him at the center of the field so that he will clear obstacles outside of the field and have sufficient space in which to roll to a stop after landing.

In Fig. 3 the container 1 has in it a micro-ray tube having a cathode 14, an oscillating electrode repulsion electrode through a potentiometer 20,

and a battery'21 supplies potential to the oscillating electrode through a potentiometer 22 in series with a choke coil 23. Modulating signals may be applied to the tube through transformer 24 and condenser 25, or when the tube is used as a detector the detected signals may be taken from the circuit by means of these elements.

What is claimed is:

1. The method of determining the direction of signalling impulses in a micro-ray system having aparaboloid reflector with a rotatably mounted reflecting screen positioned in front of the opening thereof, which comprises adjusting said system for the detection of signals and slowly revolving said screen whereby a signal is impinged upon said paraboloid reflector.

2. The method of transmitting directional waves in a micro-ray signalling system having a paraboloid reflector with a rotatably mounted screen positioned in front of the opening thereof, which comprises generating high frequency impulses and rapidly rotating said screen whereby high frequency impulses reflected by said reflector are broadcast.

3. A micro-ray directional system including a paraboloid reflector having an antenna disposed substantially at its focal point, a screen rotatably mounted and disposed a predetermined distance in front of the opening in said paraboloid reflector, and means associated with said screen adapted to cause its rotation whereby said screen may be rotated rapidly when said system is used as a directional transmitter and slowly when said system is used as a directional detector.

4. A micro-ray directional system including a paraboloid reflector having quarter-wave antennae arranged at right angles to each other and disposed substantially at its focal point, a rotatably mounted screen disposed a predetermined distance in front of the opening insaid paraboloid reflector, and means adapted to cause rotation of saidscreen whereby said screen may be rotated rapidly when said system is used as a directional transmitter and slowly when said system is used as a directional detector. 

